Until recent years, the ordinary householder carried only three or four keys; usually on a split ring or sometimes in a key case. Today, a householder may carry ten or more keys such as a house key, garage key, keys for two or more cars (trunk and ignition) security alarm key, office door key, lock box, luggage, ski or bicycle rack lock key and a miscellaneous key or two. Most people can remember which key fits which lock, but frequently the keys must be turned over to a relative or friend who is at a complete loss as to which key fits which lock. An apartment owner, hospital, school or business manager has an even more complicated problem since the number of their keys may number in the hundreds.
Usually, people store a duplicate set of keys in a safe place from which keys can be made should one or more keys be lost. Frequently, keys to seldom used lockers and pad locks for boats, summer cottages, luggage, equipment and other miscellaneous locks are stored. Here the problem is annoying since it is often difficult to remember which key fits which lock.
Present systems for labeling, storing and carrying keys are unnecessarily complex and yet limited in function. Some systems such as key rings are compact but labeling is difficult. Printed adhesive labels are available which can be used to identify certain keys, but not with the variety that a person may need to insure complete identification. Paper, plastic and metal tags are also available but these are either impermanent or hard to mark. Most of those available also have the disadvantage of being too bulky to carry in the pocket in large numbers. Many of them cannot be transferred easily from one key ring to another or to and from a hook in a cabinet or lock box. Some cannot be attached to a key ring or pocket key case.